Finding and querying documents in Express - Mini Project: Build & Apply

Finding and Querying Documents with Express and MongoDB

📖 Scenario: You are building a simple Express server that connects to a MongoDB database. The database stores a collection of books with their titles and authors.You want to create routes to find and query these book documents.

🎯 Goal: Build an Express server with a MongoDB connection that can find all books and query books by author.

📋 What You'll Learn

Create a MongoDB collection named books with sample data

Set up an Express server with MongoDB connection

Create a route to find all books

Create a route to query books by author using a query parameter

💡 Why This Matters

🌍 Real World

Web servers often need to find and filter data from databases to show users relevant information.

💼 Career

Backend developers use Express and databases like MongoDB to build APIs that find and query documents efficiently.

1

Set up the books collection with sample data

Create a constant called books that is an array of objects with these exact entries: { title: 'The Hobbit', author: 'J.R.R. Tolkien' }, { title: '1984', author: 'George Orwell' }, and { title: 'To Kill a Mockingbird', author: 'Harper Lee' }.

Express

// Create the books array with the given objects
// Your code here

Need a hint?

Use const books = [ ... ] with the exact objects inside the array.

2

Set up Express server and MongoDB connection

Create a constant called express by requiring 'express'. Then create a constant called app by calling express(). Also create a constant called port and set it to 3000.

Express

const books = [
  { title: 'The Hobbit', author: 'J.R.R. Tolkien' },
  { title: '1984', author: 'George Orwell' },
  { title: 'To Kill a Mockingbird', author: 'Harper Lee' }
];

// Set up Express server and port
// Your code here

Need a hint?

Use const express = require('express'), then const app = express(), and set const port = 3000.

3

Create route to find all books

Use app.get with the path '/books' and a callback with parameters req and res. Inside the callback, send the books array as JSON using res.json(books).

Express

const books = [
  { title: 'The Hobbit', author: 'J.R.R. Tolkien' },
  { title: '1984', author: 'George Orwell' },
  { title: 'To Kill a Mockingbird', author: 'Harper Lee' }
];

const express = require('express');
const app = express();
const port = 3000;

// Create GET route for '/books' to send all books
// Your code here

Need a hint?

Use app.get('/books', (req, res) => { res.json(books); }) to send all books.

4

Create route to query books by author

Use app.get with the path '/books/search' and a callback with req and res. Inside, get the author query parameter from req.query.author. Filter the books array to only include books where book.author exactly matches the author query. Send the filtered array as JSON with res.json(filteredBooks). Finally, start the server listening on port with app.listen(port).

Express

const books = [
  { title: 'The Hobbit', author: 'J.R.R. Tolkien' },
  { title: '1984', author: 'George Orwell' },
  { title: 'To Kill a Mockingbird', author: 'Harper Lee' }
];

const express = require('express');
const app = express();
const port = 3000;

app.get('/books', (req, res) => {
  res.json(books);
});

// Create GET route '/books/search' to filter books by author query
// Start server listening on port
// Your code here

Need a hint?

Use app.get('/books/search', (req, res) => { ... }), get author from req.query.author, filter books by exact author match, send filtered books with res.json, and start server with app.listen(port).